So, for those of us who are in the process of tower-planning, what
should we order from the local "metals supermarket" type of supplier to
use for a 20 ft. mast to hold an HF tribander and a 6m beam?
(Calculated wind load is 6 ft^2 for the tribander and 3 ft^2 for the 6m
for 9 ft^2 total wind load from the antennas ONLY.)
DeKalb County, Georgia is a 90mph county and I've specced everything out
so far to 110mph ratings for the tower.
I've found seamless steel tubing, 1/8" walls, non-galvanized, but am
concerned with how to protect the interior from corrosion if it's not
hot-dip galvanized? I can "cold-galvanize" the outside, but the
interior is a different matter.
Jim Brown wrote:
> On Fri, 05 Jun 2009 18:52:50 -0400, Roger (K8RI) wrote:
>> There are two types of rigid steel conduit. The one is like schedule 40
>> pipe and the other (EMT) is thin wall.
> Clarification: Actually, there are three thicknesses of steel conduit
> commonly used in North America. In the trade, they are designated "Rigid
> Steel Conduit," "Intermediate Metal Conduit," and Electrical Metallic
> Tubing. Wall thicknesses varies with conduit size, and for these 1.5-inch
> nominal conduits are are 0.138 in, 0.09 in, and 0.065 in respectively. I'm
> talking about using a 10 ft length of "Rigid Steel Conduit," which is 1.9
> inch o.d., with only a 3-el SteppIR at the top (which is relatively small
> and light weight).
> Jim K9YC
73 de W5NNH
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